Electrode, Secondary Battery Including the Electrode, and Method of Preparing the Electrode

Abstract

An electrode includes an electrode active material, wherein the electrode active material layer includes an electrode active material, polyvinylidene fluoride, and a conductive agent, wherein the conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other, and the carbon nanotube structure is included in an amount of 0.01 wt % to 0.5 wt % in the electrode active material layer. A secondary battery including the same, and a method of preparing the electrode are also provided.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Korean Patent Application Nos. 10-2018-0040574, filed on Apr. 6, 2018, and 10-2019-0040100, filed on Apr. 5, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.TECHNICAL FIELD

[0002] The present invention relates to an electrode, a secondary battery including the same, and a method of preparing the electrode, wherein the electrode includes an electrode active material layer, the electrode active material layer includes an electrode active material; polyvinylidene fluoride; and a conductive agent, the conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other, and the carbon nanotube structure may be included in an amount of 0.01 wt % to 0.5 wt % in the electrode active material layer.BACKGROUND ART

[0003] A typical example of an electrochemical device usin...

Examples

preparation example 1

Preparation of Conductive Agent Dispersion

[0103]0.2 part by weight of bundle type carbon nanotubes (specific surface area of 650 m2 / g) composed of single-walled carbon nanotube units having an average diameter of 1.5 nm and an average length of 5 μm and 2.0 parts by weight of polyvinylidene fluoride (weight-average molecular weight: 685,000 g / mol, standard homo-polymer) were mixed in 97.8 parts by weight of N-methylpyrrolidone (NMP), as a dispersion medium, to prepare a mixture such that a solid content was 2.2 wt %.

[0104]The bundle type carbon nanotubes were dispersed in the dispersion medium by stirring the mixture by sonication and thus, a conductive agent dispersion was prepared. In this case, the sonication was performed at a power of 1,000 W for 1.5 hours. The conductive agent dispersion included a carbon nanotube structure in the form in which 2 to 5,000 single-walled carbon nanotube units were bonded together side by side. In the conductive agent dispersion, an amount of the...

preparation example 2

Preparation of Conductive Agent Dispersion

[0105]A conductive agent dispersion was prepared in the same manner as in Preparation Example 1 except that the polyvinylidene fluoride was modified polyvinylidene fluoride (weight-average molecular weight: 880,000 g / mol) including an acid functional group in an amount of 2.1 wt %.

preparation example 3

Preparation of Conductive Agent Dispersion

[0106]4.0 parts by weight of bundle type carbon nanotubes (specific surface area of 185 m2 / g) composed of multi-walled carbon nanotube units having an average diameter of 10 nm and an average length of 1 μm and 0.8 part by weight of modified polyvinylidene fluoride (weight-average molecular weight: 880,000 g / mol) including an acid functional group in an amount of 2.1 wt % were mixed in 95.2 parts by weight of N-methylpyrrolidone (NMP), as a dispersion medium, to prepare a mixture such that a solid content was 4.8 wt %.

[0107]The bundle type carbon nanotubes were dispersed in the dispersion medium by stirring the mixture by sonication and thus, a conductive agent dispersion was prepared. In this case, the sonication was performed at a power of 1,000 W for 1.5 hours. In the conductive agent dispersion, an amount of the multi-walled carbon nanotube units was 4.0 wt %, and an amount of the polyvinylidene fluoride was 0.8 wt %.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Korean Patent Application Nos. 10-2018-0040574, filed on Apr. 6, 2018, and 10-2019-0040100, filed on Apr. 5, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.TECHNICAL FIELD

[0002] The present invention relates to an electrode, a secondary battery including the same, and a method of preparing the electrode, wherein the electrode includes an electrode active material layer, the electrode active material layer includes an electrode active material; polyvinylidene fluoride; and a conductive agent, the conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other, and the carbon nanotube structure may be included in an amount of 0.01 wt % to 0.5 wt % in the electrode active material layer.BACKGROUND ART

[0003] A typical example of an electrochemical device usin...

Examples

preparation example 1

Preparation of Conductive Agent Dispersion

[0103]0.2 part by weight of bundle type carbon nanotubes (specific surface area of 650 m2 / g) composed of single-walled carbon nanotube units having an average diameter of 1.5 nm and an average length of 5 μm and 2.0 parts by weight of polyvinylidene fluoride (weight-average molecular weight: 685,000 g / mol, standard homo-polymer) were mixed in 97.8 parts by weight of N-methylpyrrolidone (NMP), as a dispersion medium, to prepare a mixture such that a solid content was 2.2 wt %.

[0104]The bundle type carbon nanotubes were dispersed in the dispersion medium by stirring the mixture by sonication and thus, a conductive agent dispersion was prepared. In this case, the sonication was performed at a power of 1,000 W for 1.5 hours. The conductive agent dispersion included a carbon nanotube structure in the form in which 2 to 5,000 single-walled carbon nanotube units were bonded together side by side. In the conductive agent dispersion, an amount of the...

preparation example 2

Preparation of Conductive Agent Dispersion

[0105]A conductive agent dispersion was prepared in the same manner as in Preparation Example 1 except that the polyvinylidene fluoride was modified polyvinylidene fluoride (weight-average molecular weight: 880,000 g / mol) including an acid functional group in an amount of 2.1 wt %.

preparation example 3

Preparation of Conductive Agent Dispersion

[0106]4.0 parts by weight of bundle type carbon nanotubes (specific surface area of 185 m2 / g) composed of multi-walled carbon nanotube units having an average diameter of 10 nm and an average length of 1 μm and 0.8 part by weight of modified polyvinylidene fluoride (weight-average molecular weight: 880,000 g / mol) including an acid functional group in an amount of 2.1 wt % were mixed in 95.2 parts by weight of N-methylpyrrolidone (NMP), as a dispersion medium, to prepare a mixture such that a solid content was 4.8 wt %.

[0107]The bundle type carbon nanotubes were dispersed in the dispersion medium by stirring the mixture by sonication and thus, a conductive agent dispersion was prepared. In this case, the sonication was performed at a power of 1,000 W for 1.5 hours. In the conductive agent dispersion, an amount of the multi-walled carbon nanotube units was 4.0 wt %, and an amount of the polyvinylidene fluoride was 0.8 wt %.

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